Expression of GATA-3 in human tissues and neoplasms

GATA-3 è posto nel braccio corto del cromosoma 10 ed è un membro della famiglia di fattori di trascrizione GATA(1-6) che legano specifiche sequenze GATA. GATA-3 è coinvolto nella modulazione dell'espressione genica durante l'embriogenesi di molti apparati umani e delle cellule ematopoietiche e risulta altamente conservato nei vertebrati. La delezione terminale del cromosoma 10 causa una sindrome clinica chiamata sindrome HDR caratterizzata da ipoparatiroidismo, malformazioni cardiache e del sistema genito-urinario, immunodeficit e ipoacusia. Nel nostro lavoro abbiamo voluto analizzare l'espressione della proteina GATA3 tramite immunoistochimica (GATA3, Pharmigen, L50-823, 1:150) in una ampia casistica di tessuti normali e neoplastici nell'apparato urinario, della mammella e di tiroide e paratiroide. Abbiamo evidenziato che il GATA3 è espresso nell' urotelio normale e neoplastico della pelvi renale 78%) e della vescica (88%) e l'espressione è correlata al grado di differenziazione delle neoplasie. Nel rene abbiamo notato espressione nei podociti, nel dotto collettore e nei tubuli distali, mentre nella controparte neoplastiche quasi tutte le neoplasie studiate sono risultate negative tranne 4 casi di carcinoma a cellule chiare papillare e 5 casi di carcinoma a cellule chiare con prominente proliferazione leiomuscolare. I casi risultati positivi all'immunoistochimica sono stati poi confermati mediante Western-blot. Abbiamo inoltra valutato il gene VHL dei casi di carcinoma a cellule chiare papillare notando che nessun caso portava mutazioni o metilazione del gene VHL. Nella mammella abbiamo confermato i dati di letteratura che vedono il GATA3 correlare a tumori meglio differenziati e a prognosi benigna (basso grado citologico, basso indice proliferativo, espressione di ER e PgR) ma abbiamo anche evidenziato un'inaspettata positività al marcatore nei gruppo di casi tripli negativi (ER neg, Prg neg e HER 2neg). Dato che il GATA3 risulta fortemente associato all'espressione dei recettori per estrogeni, la nostra scoperta permetterebbe di individuare un sottogruppo di pazienti che potrebbero beneficiare della terapia anti-estrogenica. Il GATA3 risulta importante anche nello sviluppo degli organi endocrini del collo, nel nostro studio abbiamo evidenziato una positività del GATA3 nei solid nest della tiroide, nel parenchima normale ed in quello adenomatoso delle paratiroidi ed è risultato positivo anche in un citologico di adenoma paratiroideo, sottolineando il possibile uso in citologia per la diagnostica differenziale tra le lesioni paratiroidee (GATA3+) e quelle follicolari tiroidee (GATA3 neg).

GATA-3 (10p 14-15) is a member of transcription factor family (GATA1-6) that binds selected GATA sites to regulate specific gene expression. GATA-3 is involved in the modulation of gene expression profiles during embryogenesis of a variety of human tissues as hematopoietic cells Terminal deletions of chromosome 10p result in a DiGeorge-like fenotype characterized by hypoparathyroidism, heart defects, immune deficiecy, deafness and Renal malformation (HDR syndrome). We sought to evaluate the presence of GATA-3 protein by immunohistochemistry among a larger cohort of subtypes of carcinomas and normal tissue of urogenital tract, breast, thyroid and parathyroid, these cases were identified and retrieved from the archives of Verona University and diagnosed between 1993 to 2011. Our series includes: 86 urothelial carcinoma, 23 metastatic localization of urothelial carcinomas, 100 renal cell neoplasms, 20 prostatic adenocarcinoma, 133 normal tissue, 191 breast carcinomas, 1 citologic smear from parathyroid adenoma, 10 non-neoplastic parathyroid parenchima, 10 parathyroid adenomas, 10 solid nests in the thyroid, 10 papillary thyroid carcinoma, 5 follicular thyroid carcinomas, 20 bening hyperplastic nodules and 5 brachial cysts. We preformed an immunohistochemistry staining with mouse monoclonal anti-GATA3 was obtained from Pharmigen (L50-823, dilution 1:150). The pattern of staining was nuclear. We assesed Western blot in renal cell neoplasms wich are GATA-3 positive and in some of these cases VHL sequencing analysis and CpG methylation analysis. Regarding breast cases we had collected personal data and histological diagnosis for each case, wich include: diameter, grade, lymphonode status, estrogen receptor alpha (ER), progesterone receptor (PR), proliferation index (Ki67), HER-2. In normal kidney tissue GATA3 stained podocytes, the epithelium of distal nephron and also collector ducts; bladder urothelial epithelium showed strong GATA3 nuclear positivity; GATA3 stained some prostatic basal cells of glandular structures and basal cell of seminale vescicles. Pelvis urothelial carcinomas were positive in 78% of cases (25/32), furthermore there was evidence that tumors with good-moderate differentiation (88%) were more positive those poor-differentiated (71%). Bladder urothelial carcinomas were positive in 85% of cases (18/21) with correlation from GATA3 expression and differentiation grade of neoplasms (100% low grade vs. 75% high grade). Bladder carcinomas nested variant and micropapillary variant showed GATA3 positivity (1/1). All prostatic localizations of bladder carcinoma had showed positive immunoreaction for GATA3 (6/6). Urothelial metastatic localizations were positive in 57% of case (13/23). None prostatic adenocarcinoma swowed GATA3 positivity. In renal neoplasms we have found GATA-3 positivity in 4 of 5 clear cell-papillary renal cell carcinoma and in 5/5 clear renal cell carcinomas with prominent leiomyomatous proliferation. None other cases of renal carcinomas showed positivity to GATA-3. In 2 clear cell-papillary renal cell carcinoma and in 1 clear renal cell carcinomas with prominent leiomyomatous proliferation Western blot analysis highlighted the presence of the GATA-3 protein in cases positive at immunophenotyical level. No mutation of coding sequence of the VHL gene was found in epithelial and smooth muscle cell components of the tumors . MS-MLPA analysis of FFPE tissue DNA samples showed absent or mild methylation of VHL gene. In normal breast tissue GATA-3 stained duct luminal cell. Overall 147 breast cancer (78%) have shown GATA-3 expression. We have found statistically significance correlation from GATA-3 expression and patient age, grading of neoplasm, ER-PgR status and Ki-67 expression. In our collection all 106 ER+, PG, breast carcinoma were positive for GATA-3. Among ER-,PG-, Her2+ breast carcinoma the presence of GATA-3 was detected in 10/11 cases The most interesting and unexpected evidence of our work is GATA-3 expression in triple 31 cases of negative breast carcinoma (31/74)(41,9%). We observed strong positivity in cytologic sample of parathyroid adenoma, in all solid nests (10/10), parathyroid parenchymas (10/10), parathyroid adenomas (10/10). and in the epithelial lining of branchial cysts (5/5). On the contrary, GATA3 immunostaining was absent in all papillary (0/10) and follicular thyroid carcinomas (0/5) and in all benign hyperplastic thyroid nodules (0/20). Finally this study had highlighted that GATA3 is a good marker to reveal urothelial origin of neoplastic cells and allow to use GATA3 in the differential diagnosis between prostate carcinomas and urothelial tumors; moreover we found that urothelial tumors tend to lose GATA3 expression in low differentiated areas. Among renal cell neoplasms, we interestingly noted that only rare tumours such as clear cell-papillary renal cell carcinomas (4/5) and clear cell renal cell carcinomas with prominent leiomyomatous proliferation (5/5) were positive for GATA-3. GATA3 protein expression is confirmed by using the Western Blot analysis. In our study we found that: clear cell papillary renal cell carcinoma do not show VHL mutation and do not show CpG methylation abnormalities and may be part of this tumors subgroup lacking VHL gene alterations (WT VHL) as indicated in the recent study. Some studies are supporting the evidence that under the name “clear cell renal cell carcinoma” are included a basket of different entities. These rare cancers are difficult to diagnosis to inexperienced pathologist and in the literature reliable data for specific markers for these neoplasm are lacking. So GATA3 antibody merits to be included in the most common routinely available immunohistochemical panels and to be used for the differential diagnosis of renal cell neoplasms. Breast cancer comprises a heterogeneous group of diseases that vary in morphology, biology, behaviour and response to therapy. In our series in normal breast tissue GATA-3 stained duct luminal cell, as previously validated . Overall 147 breast cancer (78%) have showed GATA-3 expression and we demontrated GATA-3 expression statistically is correlated with patient age, ER-PgR status, grading of neoplasm and Ki-67 expression. We found that all 106 ER+/PG+, breast carcinoma were positive for GATA-3. Among ER-/PG-/Her2+ breast carcinoma the presence of GATA-3 was detected in 10/11 cases The most interesting and unexpected evidence of our work is GATA-3 expression in triple negative breast carcinoma (31/74)(41,9%). This percentage of triple negative tumors with positive GATA3 may highlight a new subgroup of tumors that benefit therapy with tamoxifen. In our series we observed strong positivity in all solid nests, parathyroid parenchymas, parathyroid adenomas and in the epithelial lining of branchial cysts. On the contrary, GATA3 immunostaining was absent in all papillary and follicular thyroid carcinomas and in all benign hyperplastic thyroid nodules. A specific use of GATA3 could be in fine needle aspiration (FNA) cytology of parathyroid lesions. No one single cytomorphologic feature is diagnostic and at the present we can use nucler antibod, TTF1, to recognise follicular lesion and a citoplasmatic antibody, PTH, to recognise parathyroid lesion. But in citologic smear it is easy that cells losing the cytoplasmic component and the diagnosis of parathyroid adenoma is possible only in a negative manner. GATA3 is a nucler marker and it can do very useful to identify parathyroid cells.